• Journal of Advanced Marine Engineering and Technology
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• v.39 no.8
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• pp.801-806
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• 2015

The experimental analysis of a crevice-type vapor chamber heat pipe (CVCHP) is investigated. The heat source of the CVCHP is a high-power light-emitting diode (LED). The CVCHP, which exhibits a bubble pumping effect, is used for heat dissipation in a high-heat-flux system. The working fluid is R-141b, and its charging ratio was set at 60 vol.% of the vapor chamber in a heat pipe. The total thermal conductivity of the falling-liquid-film-type model, which was a modified model, was 24% larger than that of the conventional model in the LED package. Flow visualization results indicated that bubbles grew larger as they combined. These combined bubbles pushed the working fluid to the top, partially wetting the heat-transfer area. The thermal resistance between the vapor chamber and tube in the modified design decreased by approximately 32%. The overall results demonstrated the better heat dissipation upon cooling of the high-power LED package.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.2
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• pp.96-101
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• 2016

The thermal management of high-power LED components in an assembly structure is crucial for the stable operation and proper luminous function. This study employs numerical tools to determine the optimum thermal design in LEDs with a heat sink consisting of a crevice-type vapor-chamber heat pipe. The effects of the MCPCB are investigated in terms of the substrate thicknesses on which the LEDs are mounted. Further, different placement configurations in a system module are considered. This study found that for a confined area, a power of 40 W/LED is applicable to a high-power package. Furthermore, the thermal conductivity of dielectric layer materials should ideally be greater than 0.9 W/m.K. The temperature conditions of the vapor chamber in a heat pipe greatly affect the thermal performance of the system. At an offset distance of 9.0 mm and a $2^{\circ}C$ increase in the temperature of the heat pipe, the resulting maximum temperature increase is approximately $1.9^{\circ}C$ for each heat dissipation temperature. Finally, at a thermal conductivity of 0.3 W/m.K, it was found that the total thermal resistance changes dramatically. Above 1.2 W/m.K, the resistance change reduces exponentially.